| Message ID | 20230702123242.232484-13-jc@kynesim.co.uk |
|---|---|
| State | New |
| Headers | show |
| Series | avfilter/vf_bwdif: Add aarch64 neon functions | expand |
| Context | Check | Description |
|---|---|---|
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | fail | Make fate failed |
Am So., 2. Juli 2023 um 14:34 Uhr schrieb John Cox <jc@kynesim.co.uk>: > Add an optional filter_line3 to the available optimisations. > > filter_line3 is equivalent to filter_line, memcpy, filter_line > > filter_line shares quite a number of loads and some calculations in > common with its next iteration and testing shows that using aarch64 > neon filter_line3s performance is 30% better than two filter_lines > and a memcpy. > > Signed-off-by: John Cox <jc@kynesim.co.uk> > --- > libavfilter/bwdif.h | 7 +++++++ > libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 38 insertions(+) > > diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h > index cce99953f3..496cec72ef 100644 > --- a/libavfilter/bwdif.h > +++ b/libavfilter/bwdif.h > @@ -35,6 +35,9 @@ typedef struct BWDIFContext { > void (*filter_edge)(void *dst, void *prev, void *cur, void *next, > int w, int prefs, int mrefs, int prefs2, int > mrefs2, > int parity, int clip_max, int spat); > + void (*filter_line3)(void *dst, int dstride, > + const void *prev, const void *cur, const void > *next, int prefs, > + int w, int parity, int clip_max); > } BWDIFContext; > > void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int bit_depth); > @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void *prev1, > void *cur1, void *next1, > int prefs3, int mrefs3, int prefs4, int > mrefs4, > int parity, int clip_max); > > +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > + const void * prev1, const void * cur1, const > void * next1, int s_stride, > + int w, int parity, int clip_max); > + > #endif /* AVFILTER_BWDIF_H */ > diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c > index 26349da1fd..52bc676cf8 100644 > --- a/libavfilter/vf_bwdif.c > +++ b/libavfilter/vf_bwdif.c > @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1, void *prev1, > void *cur1, void *next1, > FILTER2() > } > > +#define NEXT_LINE()\ > + dst += d_stride; \ > + prev += prefs; \ > + cur += prefs; \ > + next += prefs; > + > +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > + const void * prev1, const void * cur1, const > void * next1, int s_stride, > + int w, int parity, int clip_max) > +{ > + const int prefs = s_stride; > + uint8_t * dst = dst1; > + const uint8_t * prev = prev1; > + const uint8_t * cur = cur1; > + const uint8_t * next = next1; > + > + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, (void*)next, w, > + prefs, -prefs, prefs * 2, - prefs * 2, prefs * > 3, -prefs * 3, prefs * 4, -prefs * 4, parity, clip_max); > + NEXT_LINE(); > + memcpy(dst, cur, w); > + NEXT_LINE(); > + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, (void*)next, w, > + prefs, -prefs, prefs * 2, - prefs * 2, prefs * > 3, -prefs * 3, prefs * 4, -prefs * 4, parity, clip_max); > +} > + > void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void *cur1, void > *next1, > int w, int prefs, int mrefs, int prefs2, int > mrefs2, > int parity, int clip_max, int spat) > @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext *ctx, void > *arg, int jobnr, int nb_jobs) > refs << 1, -(refs << 1), > td->parity ^ td->tff, clip_max, > (y < 2) || ((y + 3) > td->h) ? 0 : 1); > + } else if (s->filter_line3 && y + 2 < slice_end && y + 6 < > td->h) { > + s->filter_line3(dst, td->frame->linesize[td->plane], > + prev, cur, next, linesize, td->w, > + td->parity ^ td->tff, clip_max); > + y += 2; > } else { > s->filter_line(dst, prev, cur, next, td->w, > refs, -refs, refs << 1, -(refs << 1), > Maybe I'm missing something, but doesn't this kick out most of the x86 SIMD optimization because there is no filter_line3?
On Sun, 2 Jul 2023, Thomas Mundt wrote: > Am So., 2. Juli 2023 um 14:34 Uhr schrieb John Cox <jc@kynesim.co.uk>: > Add an optional filter_line3 to the available optimisations. > > filter_line3 is equivalent to filter_line, memcpy, filter_line > > filter_line shares quite a number of loads and some calculations > in > common with its next iteration and testing shows that using > aarch64 > neon filter_line3s performance is 30% better than two > filter_lines > and a memcpy. > > Signed-off-by: John Cox <jc@kynesim.co.uk> > --- > libavfilter/bwdif.h | 7 +++++++ > libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 38 insertions(+) > > diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h > index cce99953f3..496cec72ef 100644 > --- a/libavfilter/bwdif.h > +++ b/libavfilter/bwdif.h > @@ -35,6 +35,9 @@ typedef struct BWDIFContext { > void (*filter_edge)(void *dst, void *prev, void *cur, void > *next, > int w, int prefs, int mrefs, int > prefs2, int mrefs2, > int parity, int clip_max, int spat); > + void (*filter_line3)(void *dst, int dstride, > + const void *prev, const void *cur, > const void *next, int prefs, > + int w, int parity, int clip_max); > } BWDIFContext; > > void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int > bit_depth); > @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void > *prev1, void *cur1, void *next1, > int prefs3, int mrefs3, int prefs4, > int mrefs4, > int parity, int clip_max); > > +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > + const void * prev1, const void * > cur1, const void * next1, int s_stride, > + int w, int parity, int clip_max); > + > #endif /* AVFILTER_BWDIF_H */ > diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c > index 26349da1fd..52bc676cf8 100644 > --- a/libavfilter/vf_bwdif.c > +++ b/libavfilter/vf_bwdif.c > @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1, > void *prev1, void *cur1, void *next1, > FILTER2() > } > > +#define NEXT_LINE()\ > + dst += d_stride; \ > + prev += prefs; \ > + cur += prefs; \ > + next += prefs; > + > +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > + const void * prev1, const void * > cur1, const void * next1, int s_stride, > + int w, int parity, int clip_max) > +{ > + const int prefs = s_stride; > + uint8_t * dst = dst1; > + const uint8_t * prev = prev1; > + const uint8_t * cur = cur1; > + const uint8_t * next = next1; > + > + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, > (void*)next, w, > + prefs, -prefs, prefs * 2, - prefs * > 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, > clip_max); > + NEXT_LINE(); > + memcpy(dst, cur, w); > + NEXT_LINE(); > + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, > (void*)next, w, > + prefs, -prefs, prefs * 2, - prefs * > 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, > clip_max); > +} > + > void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void > *cur1, void *next1, > int w, int prefs, int mrefs, int > prefs2, int mrefs2, > int parity, int clip_max, int spat) > @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext > *ctx, void *arg, int jobnr, int nb_jobs) > refs << 1, -(refs << 1), > td->parity ^ td->tff, clip_max, > (y < 2) || ((y + 3) > td->h) ? 0 > : 1); > + } else if (s->filter_line3 && y + 2 < slice_end && > y + 6 < td->h) { > + s->filter_line3(dst, > td->frame->linesize[td->plane], > + prev, cur, next, linesize, > td->w, > + td->parity ^ td->tff, > clip_max); > + y += 2; > } else { > s->filter_line(dst, prev, cur, next, td->w, > refs, -refs, refs << 1, -(refs > << 1), > > > Maybe I'm missing something, but doesn't this kick out most of the x86 SIMD > optimization because there is no filter_line3? It looks to me like it doesn't; it adds a new optional function pointer, but the reference C function isn't set. So by default (and on x86) filter_line3 is null, and the old assembly optimized codepaths are used. But if an architecture does implement filter_line3, that's used instead of filter_line. // Martin
On Mon, 3 Jul 2023 00:12:46 +0300 (EEST), you wrote: >On Sun, 2 Jul 2023, Thomas Mundt wrote: > >> Am So., 2. Juli 2023 um 14:34 Uhr schrieb John Cox <jc@kynesim.co.uk>: >> Add an optional filter_line3 to the available optimisations. >> >> filter_line3 is equivalent to filter_line, memcpy, filter_line >> >> filter_line shares quite a number of loads and some calculations >> in >> common with its next iteration and testing shows that using >> aarch64 >> neon filter_line3s performance is 30% better than two >> filter_lines >> and a memcpy. >> >> Signed-off-by: John Cox <jc@kynesim.co.uk> >> --- >> libavfilter/bwdif.h | 7 +++++++ >> libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++ >> 2 files changed, 38 insertions(+) >> >> diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h >> index cce99953f3..496cec72ef 100644 >> --- a/libavfilter/bwdif.h >> +++ b/libavfilter/bwdif.h >> @@ -35,6 +35,9 @@ typedef struct BWDIFContext { >> void (*filter_edge)(void *dst, void *prev, void *cur, void >> *next, >> int w, int prefs, int mrefs, int >> prefs2, int mrefs2, >> int parity, int clip_max, int spat); >> + void (*filter_line3)(void *dst, int dstride, >> + const void *prev, const void *cur, >> const void *next, int prefs, >> + int w, int parity, int clip_max); >> } BWDIFContext; >> >> void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int >> bit_depth); >> @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void >> *prev1, void *cur1, void *next1, >> int prefs3, int mrefs3, int prefs4, >> int mrefs4, >> int parity, int clip_max); >> >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, >> + const void * prev1, const void * >> cur1, const void * next1, int s_stride, >> + int w, int parity, int clip_max); >> + >> #endif /* AVFILTER_BWDIF_H */ >> diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c >> index 26349da1fd..52bc676cf8 100644 >> --- a/libavfilter/vf_bwdif.c >> +++ b/libavfilter/vf_bwdif.c >> @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1, >> void *prev1, void *cur1, void *next1, >> FILTER2() >> } >> >> +#define NEXT_LINE()\ >> + dst += d_stride; \ >> + prev += prefs; \ >> + cur += prefs; \ >> + next += prefs; >> + >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, >> + const void * prev1, const void * >> cur1, const void * next1, int s_stride, >> + int w, int parity, int clip_max) >> +{ >> + const int prefs = s_stride; >> + uint8_t * dst = dst1; >> + const uint8_t * prev = prev1; >> + const uint8_t * cur = cur1; >> + const uint8_t * next = next1; >> + >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, >> (void*)next, w, >> + prefs, -prefs, prefs * 2, - prefs * >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, >> clip_max); >> + NEXT_LINE(); >> + memcpy(dst, cur, w); >> + NEXT_LINE(); >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, >> (void*)next, w, >> + prefs, -prefs, prefs * 2, - prefs * >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, >> clip_max); >> +} >> + >> void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void >> *cur1, void *next1, >> int w, int prefs, int mrefs, int >> prefs2, int mrefs2, >> int parity, int clip_max, int spat) >> @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext >> *ctx, void *arg, int jobnr, int nb_jobs) >> refs << 1, -(refs << 1), >> td->parity ^ td->tff, clip_max, >> (y < 2) || ((y + 3) > td->h) ? 0 >> : 1); >> + } else if (s->filter_line3 && y + 2 < slice_end && >> y + 6 < td->h) { >> + s->filter_line3(dst, >> td->frame->linesize[td->plane], >> + prev, cur, next, linesize, >> td->w, >> + td->parity ^ td->tff, >> clip_max); >> + y += 2; >> } else { >> s->filter_line(dst, prev, cur, next, td->w, >> refs, -refs, refs << 1, -(refs >> << 1), >> >> >> Maybe I'm missing something, but doesn't this kick out most of the x86 SIMD >> optimization because there is no filter_line3? > >It looks to me like it doesn't; it adds a new optional function pointer, >but the reference C function isn't set. So by default (and on x86) >filter_line3 is null, and the old assembly optimized codepaths are used. >But if an architecture does implement filter_line3, that's used instead of >filter_line. Indeed - that is both the intent and what appears to occur when I test it. I'd have made the C line3 function call down to line if I had any context that allowed it but passing a real context seemed against the spirit of nearly all the asm optimisations. Regards JC
Am Mo., 3. Juli 2023 um 10:27 Uhr schrieb John Cox <jc@kynesim.co.uk>: > On Mon, 3 Jul 2023 00:12:46 +0300 (EEST), you wrote: > > >On Sun, 2 Jul 2023, Thomas Mundt wrote: > > > >> Am So., 2. Juli 2023 um 14:34 Uhr schrieb John Cox <jc@kynesim.co.uk>: > >> Add an optional filter_line3 to the available optimisations. > >> > >> filter_line3 is equivalent to filter_line, memcpy, filter_line > >> > >> filter_line shares quite a number of loads and some calculations > >> in > >> common with its next iteration and testing shows that using > >> aarch64 > >> neon filter_line3s performance is 30% better than two > >> filter_lines > >> and a memcpy. > >> > >> Signed-off-by: John Cox <jc@kynesim.co.uk> > >> --- > >> libavfilter/bwdif.h | 7 +++++++ > >> libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++ > >> 2 files changed, 38 insertions(+) > >> > >> diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h > >> index cce99953f3..496cec72ef 100644 > >> --- a/libavfilter/bwdif.h > >> +++ b/libavfilter/bwdif.h > >> @@ -35,6 +35,9 @@ typedef struct BWDIFContext { > >> void (*filter_edge)(void *dst, void *prev, void *cur, void > >> *next, > >> int w, int prefs, int mrefs, int > >> prefs2, int mrefs2, > >> int parity, int clip_max, int spat); > >> + void (*filter_line3)(void *dst, int dstride, > >> + const void *prev, const void *cur, > >> const void *next, int prefs, > >> + int w, int parity, int clip_max); > >> } BWDIFContext; > >> > >> void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int > >> bit_depth); > >> @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void > >> *prev1, void *cur1, void *next1, > >> int prefs3, int mrefs3, int prefs4, > >> int mrefs4, > >> int parity, int clip_max); > >> > >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > >> + const void * prev1, const void * > >> cur1, const void * next1, int s_stride, > >> + int w, int parity, int clip_max); > >> + > >> #endif /* AVFILTER_BWDIF_H */ > >> diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c > >> index 26349da1fd..52bc676cf8 100644 > >> --- a/libavfilter/vf_bwdif.c > >> +++ b/libavfilter/vf_bwdif.c > >> @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1, > >> void *prev1, void *cur1, void *next1, > >> FILTER2() > >> } > >> > >> +#define NEXT_LINE()\ > >> + dst += d_stride; \ > >> + prev += prefs; \ > >> + cur += prefs; \ > >> + next += prefs; > >> + > >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, > >> + const void * prev1, const void * > >> cur1, const void * next1, int s_stride, > >> + int w, int parity, int clip_max) > >> +{ > >> + const int prefs = s_stride; > >> + uint8_t * dst = dst1; > >> + const uint8_t * prev = prev1; > >> + const uint8_t * cur = cur1; > >> + const uint8_t * next = next1; > >> + > >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, > >> (void*)next, w, > >> + prefs, -prefs, prefs * 2, - prefs * > >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, > >> clip_max); > >> + NEXT_LINE(); > >> + memcpy(dst, cur, w); > >> + NEXT_LINE(); > >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, > >> (void*)next, w, > >> + prefs, -prefs, prefs * 2, - prefs * > >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, > >> clip_max); > >> +} > >> + > >> void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void > >> *cur1, void *next1, > >> int w, int prefs, int mrefs, int > >> prefs2, int mrefs2, > >> int parity, int clip_max, int spat) > >> @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext > >> *ctx, void *arg, int jobnr, int nb_jobs) > >> refs << 1, -(refs << 1), > >> td->parity ^ td->tff, clip_max, > >> (y < 2) || ((y + 3) > td->h) ? 0 > >> : 1); > >> + } else if (s->filter_line3 && y + 2 < slice_end && > >> y + 6 < td->h) { > >> + s->filter_line3(dst, > >> td->frame->linesize[td->plane], > >> + prev, cur, next, linesize, > >> td->w, > >> + td->parity ^ td->tff, > >> clip_max); > >> + y += 2; > >> } else { > >> s->filter_line(dst, prev, cur, next, td->w, > >> refs, -refs, refs << 1, -(refs > >> << 1), > >> > >> > >> Maybe I'm missing something, but doesn't this kick out most of the x86 > SIMD > >> optimization because there is no filter_line3? > > > >It looks to me like it doesn't; it adds a new optional function pointer, > >but the reference C function isn't set. So by default (and on x86) > >filter_line3 is null, and the old assembly optimized codepaths are used. > >But if an architecture does implement filter_line3, that's used instead > of > >filter_line. > > Indeed - that is both the intent and what appears to occur when I test > it. I'd have made the C line3 function call down to line if I had any > context that allowed it but passing a real context seemed against the > spirit of nearly all the asm optimisations. > You´re right. Thanks.
diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h index cce99953f3..496cec72ef 100644 --- a/libavfilter/bwdif.h +++ b/libavfilter/bwdif.h @@ -35,6 +35,9 @@ typedef struct BWDIFContext { void (*filter_edge)(void *dst, void *prev, void *cur, void *next, int w, int prefs, int mrefs, int prefs2, int mrefs2, int parity, int clip_max, int spat); + void (*filter_line3)(void *dst, int dstride, + const void *prev, const void *cur, const void *next, int prefs, + int w, int parity, int clip_max); } BWDIFContext; void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int bit_depth); @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void *prev1, void *cur1, void *next1, int prefs3, int mrefs3, int prefs4, int mrefs4, int parity, int clip_max); +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, + const void * prev1, const void * cur1, const void * next1, int s_stride, + int w, int parity, int clip_max); + #endif /* AVFILTER_BWDIF_H */ diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c index 26349da1fd..52bc676cf8 100644 --- a/libavfilter/vf_bwdif.c +++ b/libavfilter/vf_bwdif.c @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1, void *prev1, void *cur1, void *next1, FILTER2() } +#define NEXT_LINE()\ + dst += d_stride; \ + prev += prefs; \ + cur += prefs; \ + next += prefs; + +void ff_bwdif_filter_line3_c(void * dst1, int d_stride, + const void * prev1, const void * cur1, const void * next1, int s_stride, + int w, int parity, int clip_max) +{ + const int prefs = s_stride; + uint8_t * dst = dst1; + const uint8_t * prev = prev1; + const uint8_t * cur = cur1; + const uint8_t * next = next1; + + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, (void*)next, w, + prefs, -prefs, prefs * 2, - prefs * 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, clip_max); + NEXT_LINE(); + memcpy(dst, cur, w); + NEXT_LINE(); + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur, (void*)next, w, + prefs, -prefs, prefs * 2, - prefs * 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity, clip_max); +} + void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void *cur1, void *next1, int w, int prefs, int mrefs, int prefs2, int mrefs2, int parity, int clip_max, int spat) @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) refs << 1, -(refs << 1), td->parity ^ td->tff, clip_max, (y < 2) || ((y + 3) > td->h) ? 0 : 1); + } else if (s->filter_line3 && y + 2 < slice_end && y + 6 < td->h) { + s->filter_line3(dst, td->frame->linesize[td->plane], + prev, cur, next, linesize, td->w, + td->parity ^ td->tff, clip_max); + y += 2; } else { s->filter_line(dst, prev, cur, next, td->w, refs, -refs, refs << 1, -(refs << 1), @@ -357,6 +387,7 @@ static int config_props(AVFilterLink *link) av_cold void ff_bwdif_init_filter_line(BWDIFContext *s, int bit_depth) { + s->filter_line3 = 0; if (bit_depth > 8) { s->filter_intra = filter_intra_16bit; s->filter_line = filter_line_c_16bit;
Add an optional filter_line3 to the available optimisations. filter_line3 is equivalent to filter_line, memcpy, filter_line filter_line shares quite a number of loads and some calculations in common with its next iteration and testing shows that using aarch64 neon filter_line3s performance is 30% better than two filter_lines and a memcpy. Signed-off-by: John Cox <jc@kynesim.co.uk> --- libavfilter/bwdif.h | 7 +++++++ libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)